High-voltage batteries for vehicle applications contain individual cells that are connected in series and/or in parallel. In the operating state, the individual cells, such as, for example, lithium ion cells, are heated to an operating temperature or else cooled in order to dissipate ensuing heat loss. For this purpose, means suitable for heat exchange are required in the battery. The individual cells are usually combined into cell modules, of which the battery comprises a large number.
In the case of liquid cooling, which is preferably used for reasons of packing space, a thermally conductive plate, through which circulates a cooling fluid, is arranged at a component assembly comprising a plurality of cell modules, and the cell modules are in thermally conductive connection with it. The cell modules are therefore cooled indirectly by way of a housing. Different forms of construction of the thermally conductive plate have been proposed.
DE 10 2016 008 110 A1 discloses a bottom plate for a battery, in particular a traction battery, which serves as a thermally conductive plate for the battery. The bottom plate is produced from extrusion-molded profiles and fixed with pipes, through which circulates cooling water, and are arranged in a meandering pattern.
Known from DE 10 2010 013 025 A1 are a battery and a method for producing a battery with a cooling plate that is arranged in a battery housing. The battery housing is cooled by the cooling plate, in which cooling channels, which are produced in an extrusion molding method, are arranged in a meandering form.
DE 10 2013 107 668 A1 discloses a battery with a cell carrier or module carrier having at least one cooling channel, with which battery cells or battery modules are thermally connected. In the production of the cell carrier or module carrier, the cooling channel is cast in it during the same casting operation as for the cell carrier or module carrier.
The use of thermally conductive plates of this kind entails a number of drawbacks. The cooling system is inefficient, because it is necessary to cool all the way through a plurality of layers (e.g., CDP coating, adhesive, gap filler) and a large part of the cooling performance is lost at the housing. The construction makes the battery complex, expensive, and heavy. Tolerances need to be taken into consideration due to welding distortions and a number of tolerance additions. As a result of this, there is high cost for planning, simulation, and design. Much area and high investments are required for fabrication of the battery. The search for leakages in the cooling circuit necessitates tedious and expensive checks. When a part of the cooling is not leaktight or is damaged, a high cost for reworking or for service or customer service thereby results. The battery must then be taken apart completely or, if need be, completely replaced. Any leakage of the cooling entails the replacement of the entire housing.